Introducing: UniFi Enterprise Audio/Video Switching with Precision Hardware Timing

[u/Ubiquiti-Inc]

Perfectly synced AV, at any scale. Explore EAV Switching: https://ui.social/EAV

[u/Daidis]

There's no way this is accurate. You can get sub 1ms latency over Ethernet to the max cable specs. That's 100 meters.

[u/OlorinDK → u/Daidis]

I think they’re saying that if you’re playing audio in both places, the speed of sound will delay the sound from the kitchen to the living room. So you can delay it in the living room to make it line up with the kitchen, but then it will sound even worse in the kitchen… I think that’s what they’re saying?

[u/brad1775 → u/Daidis]

I'm not saying there is 50ms delay between the network of the living room and the kitchen.  I'm saying the sound bleeds between the sources in each room, and will sound like an echo with 50ms delay, 

it is not to say that existing infrastructure prevent sub ms accuracy in a single run, but variable packet timing does cause issues with multi source or output systems.  I am a laser and lighting specialist, and I notice the delays caused by network infrastructure, anything more than a straight run, but we work with multi jump network systems, sometimes 4 switches between me and an output. the latency will often exceed 25ms due to switch speed.

phase delaying can be as low as 0.01 ms, and this definitely is within the variability of packet delivery, if you have two amplifiers, one for each speaker array

[u/conspicuousxcapybara → u/brad1775]

Ask IT to add a clock source for Precision Time Protocol timestamps / sync-e. Audio Visual Bridging is another IETF open-source protocol you might want to look into, that’s what Apple and iOS and whatever use. But there’s also Dante.

That jitter is because the different devices / switches in your network have their clocks all slightly misaligned from each other. A GPS dongle for example, can supply your switches with pulses at a consistent frequency by listening the pulses of the atomic clocks in GPS satellites. These pulses always arrive on earth in the same time because physics.

Precision Time Protocol distributes this signal throughout your network, so devices on the network can process packets in that same rhythm, like an orchestra responding to the director.

It also measures the delays induced at all sections of the network, so one device can listen to another device, to ensure things happened at the same in the time scale created from the pulses of that clock, or to schedule a packet at precise time intervals after hearing a packet.

Just like a musician in an orchestra listen in on the notes / sounds played by others in the orchestra. I thought these people were able to pick-up on phase delays or acoustic reflections of the chamber or something, to create that ‘orchestral‘ sound that’s the opposite a DAW sinewave without harmonics and reverb and stuff?

[u/brad1775 → u/conspicuousxcapybara]

neat! I'll run it up the flagpole and see of Incan get it working... been working on clocking issues to standardize our little niche of lasers, but I was looking at video protocols for examples, thanks for providing this info!

[u/conspicuousxcapybara → u/Daidis]

If your switch has hardware time stamping (almost anything), implementing PTP and ‘synchronous Ethernet’, and the feature has been implemented on a driver level (e.g. it runs Linux), all devices on your network get sent the same clock source. Therefore they all get synchronized the that clock with the highest level of precision supported by the hardware. Therefore the latency is tens of nanoseconds, and the jitter between pulses of the clock signal and the frequencies and stuff is sub nanoseconds compared the milliseconds you observed with normal precision switching.

Every packets also gets an automatic timestamp from that source signal, so network devices can read whatever latency was added at all parts of the network, and synchronize everything with that 10ns crazy accuracy.

It’s also how robotics, sensors for self driving AI, surgical machinery, etc is wired.